<http://webisa.webdatacommons.org/prov/509130898>	<http://www.w3.org/ns/prov#wasDerivedFrom>	<http://webisa.webdatacommons.org/227379174> .
<http://webisa.webdatacommons.org/227379174>	<http://www.w3.org/1999/02/22-rdf-syntax-ns#type>	<http://www.w3.org/ns/prov#Entity> .
<http://webisa.webdatacommons.org/prov/187458618>	<http://www.w3.org/ns/prov#wasDerivedFrom>	<http://webisa.webdatacommons.org/227379174> .
<http://webisa.webdatacommons.org/227379174>	<http://www.w3.org/ns/prov#wasQuotedFrom>	<docstoc.com> .
<http://webisa.webdatacommons.org/227379174>	<http://www.w3.org/ns/prov#value>	" Hydrogen sulfide, H2S, is a naturally occurring gas." .